[v2,19/29] tcg: Make use of bswap flags in tcg_gen_qemu_ld_*

Message ID 20210621231849.1871164-20-richard.henderson@linaro.org
State Superseded
Headers show
Series
  • tcg: bswap improvements
Related show

Commit Message

Richard Henderson June 21, 2021, 11:18 p.m.
We can perform any required sign-extension via TCG_BSWAP_OS.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 tcg/tcg-op.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

-- 
2.25.1

Comments

Philippe Mathieu-Daudé June 22, 2021, 6:46 a.m. | #1
On 6/22/21 1:18 AM, Richard Henderson wrote:
> We can perform any required sign-extension via TCG_BSWAP_OS.

> 

> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

> ---

>  tcg/tcg-op.c | 24 ++++++++++--------------

>  1 file changed, 10 insertions(+), 14 deletions(-)


Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

Patch

diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c
index 949cbf2f03..0eac2d1969 100644
--- a/tcg/tcg-op.c
+++ b/tcg/tcg-op.c
@@ -2876,7 +2876,7 @@  void tcg_gen_qemu_ld_i32(TCGv_i32 val, TCGv addr, TCGArg idx, MemOp memop)
     orig_memop = memop;
     if (!TCG_TARGET_HAS_MEMORY_BSWAP && (memop & MO_BSWAP)) {
         memop &= ~MO_BSWAP;
-        /* The bswap primitive requires zero-extended input.  */
+        /* The bswap primitive benefits from zero-extended input.  */
         if ((memop & MO_SSIZE) == MO_SW) {
             memop &= ~MO_SIGN;
         }
@@ -2889,10 +2889,9 @@  void tcg_gen_qemu_ld_i32(TCGv_i32 val, TCGv addr, TCGArg idx, MemOp memop)
     if ((orig_memop ^ memop) & MO_BSWAP) {
         switch (orig_memop & MO_SIZE) {
         case MO_16:
-            tcg_gen_bswap16_i32(val, val, TCG_BSWAP_IZ | TCG_BSWAP_OZ);
-            if (orig_memop & MO_SIGN) {
-                tcg_gen_ext16s_i32(val, val);
-            }
+            tcg_gen_bswap16_i32(val, val, (orig_memop & MO_SIGN
+                                           ? TCG_BSWAP_IZ | TCG_BSWAP_OS
+                                           : TCG_BSWAP_IZ | TCG_BSWAP_OZ));
             break;
         case MO_32:
             tcg_gen_bswap32_i32(val, val);
@@ -2965,7 +2964,7 @@  void tcg_gen_qemu_ld_i64(TCGv_i64 val, TCGv addr, TCGArg idx, MemOp memop)
     orig_memop = memop;
     if (!TCG_TARGET_HAS_MEMORY_BSWAP && (memop & MO_BSWAP)) {
         memop &= ~MO_BSWAP;
-        /* The bswap primitive requires zero-extended input.  */
+        /* The bswap primitive benefits from zero-extended input.  */
         if ((memop & MO_SIGN) && (memop & MO_SIZE) < MO_64) {
             memop &= ~MO_SIGN;
         }
@@ -2976,18 +2975,15 @@  void tcg_gen_qemu_ld_i64(TCGv_i64 val, TCGv addr, TCGArg idx, MemOp memop)
     plugin_gen_mem_callbacks(addr, info);
 
     if ((orig_memop ^ memop) & MO_BSWAP) {
+        int flags = (orig_memop & MO_SIGN
+                     ? TCG_BSWAP_IZ | TCG_BSWAP_OS
+                     : TCG_BSWAP_IZ | TCG_BSWAP_OZ);
         switch (orig_memop & MO_SIZE) {
         case MO_16:
-            tcg_gen_bswap16_i64(val, val, TCG_BSWAP_IZ | TCG_BSWAP_OZ);
-            if (orig_memop & MO_SIGN) {
-                tcg_gen_ext16s_i64(val, val);
-            }
+            tcg_gen_bswap16_i64(val, val, flags);
             break;
         case MO_32:
-            tcg_gen_bswap32_i64(val, val, TCG_BSWAP_IZ | TCG_BSWAP_OZ);
-            if (orig_memop & MO_SIGN) {
-                tcg_gen_ext32s_i64(val, val);
-            }
+            tcg_gen_bswap32_i64(val, val, flags);
             break;
         case MO_64:
             tcg_gen_bswap64_i64(val, val);